Summing the Parts of The Smiley Series

Is the whole greater?

Each individual book of the Smiley Series barring, perhaps, the latter two books of the Karla Trilogy, can be read happily on its own. There are no carryover plot threads, and the relationships and characters are re-established in each one. What I would like to ask is: is it even reasonable to try and view these books as a whole?

( Spoilers for just a metric fuckton of stuff ahoy )

I wrote this because I am procrastinating a paper tbh.